This invention relates to a stick lever device adapted to control a resistance value of a variable resistor in response to operation of a stick lever, and more particularly to an improvement in a mechanism for automatically returning a stick lever. The present invention may be applied to a radio control system for carrying out remote control of a controlled model depending on the amount of operation of the stick lever.
In general, a radio control device for remotely controlling movement of a controlled model such as a model car, a model boat, a model airplane, a model helicopter or the like includes a transmitter which is provided with a stick lever device for controlling a resistance value of a variable resistor in response to the amount of operation of the stick lever. Then, the stick lever device controls electrical radiation transmitted from the transmitter to control the amount of driving of a servo mechanism or the like mounted on the controlled model, resulting in controlling a speed of traveling of the controlled model, a direction thereof and the like.
The stick lever device is generally provided with a mechanism for automatically returning the stick lever. The mechanism is adapted to automatically return the stick lever to a predetermined neutral position when an operator releases the stick lever.
Also, for example, when a model car is to be forward and rearward moved, it is not required to control a speed at which the model car is rearward driven over a wide range as compared with that at which it is forward driven. This is true of a model boat. A model airplane does not require its rearward movement. For these reasons, a mechanism is often provided which is adapted to vary the neutral position of the stick lever in the stick lever device depending on the magnitude of operation of the stick lever required depending on the type of a controlled model.
Now, a conventional stick lever device which is provided with a mechanism for varying a neutral position of a stick lever will be described hereinafter with reference to FIG. 3 and FIGS. 4(a) and 4(b).
The mechanism includes a mounting member 100 which is mounted thereon with a variable resistor 103 through a trim lever 101 and a seat plate 102. The variable resistor 103 includes a revolving shaft 104 rotatably supported on a side of the mounting member 100. The revolving shaft 104 is fixedly mounted thereon with a drum 105, which includes a stick lever 106, so that operation of the stick lever 106 permits the revolving shaft 104 to be pivotally moved. The mounting member 100 is also provided with a change-over lever 107, which is adapted to be pivotally moved about the revolving shaft 104 and selectively held in two different positions on a side of the mounting member 100 by means of a pair of pawls 108. The change-over lever 107 is mounted with an arm member 109, which is supported at one end thereof on one end of the change-over lever 107 and mounted at the other end thereof on the other end of the change-over lever 107 through a spring 110. The arm member 109 is abutted at a central portion thereof against two projections 111 and 112 provided on a side surface of the drum 105 by means of the spring 110.
The arm member 109, as shown in FIG. 4(a), urges the projections 111 and 112 provided on the drum 105 by force of a predetermined magnitude, so that the drum 105 and stick lever 106 each are set at a predetermined neutral position. As shown in FIG. 4(b), tilting of the arm member 109 due to operation of the change-over lever 107 causes a position at which each of the drum 105 and stick lever 106 is kept stationary to be varied correspondingly.
Unfortunately, the conventional stick lever device is complicated in structure, increased in the number of parts of the device and troublesome in assembling.